This invention relates to an apparatus for connecting a small diameter tubing to a conduit in another piece of apparatus that is in communication with or handles pressure fluid in high pressure service, say, up to 60,000 lb. per square inch pressure.
There are many instances in industry where it is necessary to employ a small diameter tubing to handle a gas or liquid under high pressure. Since in many instances the gas or fluid may be corrosive in nature and the tubing is placed in inaccessable location, i.e., in a well annulus, it is desirable to employ tubing fittings that will withstand many years of usage without failure.
Tubing fittings in accordance with the present invention are employed, for example, in high pressure offshore oil and gas wells where the pressure may range from 10 to 30,000 pounds per square inch. Since it is often very difficult and extremely expensive to replace failed fittings in a high pressure well or in its wellhead assembly, it is desirable to provide tubing connectors for the well that will last the expected life of the well, say, 20 years. In the event of failure of one sealing surface or sealing area, it is desirable to have a backup or auxiliary sealing area on a tubing connector fitting which by itself can positively seal a tubing to a piece of equipment used in high pressure service.